Methods for using a support backer board system for siding

ABSTRACT

A method for using a support backer board system and siding. The support backer board system comprises at least a first layer. The first layer is made from a material selected from the group consisting of alkenyl aromatic polymers, polyolefins, polyethylene terephthalate, polyesters, and combinations thereof. The board system is thermoformed into a desired shape with the desired shape being generally contour to the selected siding. The siding is attached to the board system so as to provide support thereto. In one process, the siding may be vinyl.

FIELD OF THE INVENTION

[0001] The present invention is directed to methods for using a supportbacker board system in siding applications. In particular, the presentinvention is directed to methods for using a backer board system thatprovides support to siding, such as vinyl siding.

BACKGROUND OF THE INVENTION

[0002] The application of siding to various structures has been knownfor many years. Siding may be used in new construction in bothresidential and commercial structures, as well as in remodeling of thosestructures (also referred to as “retrofitting”). The siding may be madefrom different materials, such as vinyl, aluminum, steel, softwood, woodcomposites, and hardwood. To reduce costs, vinyl siding has generallybecome more lightweight or flimsier as compared to its inception. Thisvinyl siding is, thus, more susceptible to being deformed, breaking,and/or having a wavy appearance that is generally not aestheticallypleasing to a customer. For example, vinyl siding may be deformed orbowed (also referred to as “cupping”).

[0003] Backer boards have been used in connection with vinyl siding. Forexample, beadboard (expanded polystyrene foam or EPS foam) has been usedwith vinyl siding. Beadboard, however, has disadvantages, such as beingsusceptible to breaking during or before installation, as well as beinglabor intensive during installation.

[0004] At least one type of beadboard is molded into shapes by steamheating so as to conform to individual siding designs. The moldedbeadboard is formed in narrow pieces of varying lengths. These narrowpieces may be glued by the manufacturer or may be dropped in behind thesiding by the installer. The installation of narrow beadboard piecesresults in more opportunities for air leakage between adjacent pieces.

[0005] Another backer board that has been used with vinyl sidinginvolves using a plurality of foam profile strips that areintermittently located behind the siding. Each foam profile strip isgenerally flat with a double-sided adhesive strip attached thereto inwhich each strip is adapted to attach to a portion of a back side of thevinyl siding. The use of foam profile strips has disadvantages, such asbeing labor intensive to install, while not providing the desiredsupport.

[0006] Accordingly, a need exists for a backer board system that avoidsthe above-described problems, while providing support to the sidingapplication.

SUMMARY OF THE INVENTION

[0007] According to one method of the present invention, a supportbacker board system and siding are used. The support backer board systemcomprises at least a first layer. The first layer is extruded and madefrom a material selected from the group consisting of alkenyl aromaticpolymers, polyolefins, polyethylene terephthalate, polyesters, andcombinations thereof. The board system is thermoformed into a desiredshape that is generally contour to the selected siding. Siding isprovided and attached to the board system so as to provide supportthereto.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Other objects and advantages of the invention will becomeapparent upon reading the following detailed description and uponreference to the drawings.

[0009]FIG. 1 is a side view of the support backer board according to oneembodiment used in the present invention.

[0010]FIG. 2 is a side view of the support backer board according toanother embodiment used in the present invention.

[0011]FIG. 3 is a side view of the support backer board according to yetanother embodiment used in the present invention.

[0012]FIG. 4a is a perspective view of a siding system that has been cutaway using the support backer board of FIG. 1 in the present invention.

[0013]FIG. 4b is a side view of a portion of the siding system of FIG.4a.

[0014]FIG. 5 is a front view of siding according to one embodiment.

[0015]FIG. 6 is a schematic flow diagram of an overall sequence ofoperations according to one embodiment involved in the manufacture of asupport backer board.

[0016]FIGS. 7a and 7 b are schematic flow diagrams of an overallsequence of operations according to one embodiment involved in themanufacture of a support backer board.

[0017] While the invention is susceptible to various modifications andalternative forms, a specific embodiment thereof has been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed but, on the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theappended claims.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Support Backer Board System

[0018] According to one embodiment of the present invention, supportbacker board system 10 is shown in FIG. 1 as including first layer 12.According to another embodiment, support backer board system 10 is shownin FIG. 2 as including first layer 12 located between second layer 14and another second layer 14. Additional layers may be added to supportbacker board system 10 to bond any of the adjacent layers together. Forexample, FIG. 3 shows an alternative embodiment where support backerboard 10 includes first layer 12 located between second layer 14 andthird layer 16 and fourth layer 18 located adjacent to third layer 16.Third layer 16 is an adhesive layer in FIG. 3.

[0019]FIG. 4a illustrates a perspective view of a siding systemaccording to one embodiment that has been cut away using the supportbacker board of FIG. 1. FIG. 4b illustrates a side view of a portion ofFIG. 4a. Siding system 20 of FIGS. 4a and 4 b includes support backerboard system 10, siding 22, and plywood 24. Support backer board system10 of FIGS. 4a and 4 b is located on an interior surface of siding 22,while plywood 24 is located on an interior surface of support backerboard system 10. FIG. 5 depicts a front view of the siding according toone embodiment that includes a plurality of holes or slots 25.

First Layer

[0020] Referring to FIGS. 1-3, first layer 12 of support backer boardsystem 10 may be independently formed from any of the following resins:alkenyl aromatic polymers, polyolefins, polyethylene terephthalate(PET), polyesters, and combinations thereof. First layer 12 is generallyfrom about 125-500 mils in thickness, with a preferred thickness fromabout 250-375 mils.

[0021] The term “alkenyl aromatic polymer,” as used herein, includespolymers of aromatic hydrocarbon molecules which contain an aryl groupjoined to an olefinic group with only double bonds in the linearstructure, such as styrene, α-methylstyrene, o-methylstyrene,m-methylstyrene, p-methylstyrene, α-ethylstyrene, α-vinylxylene,α-chlorostyrene, α-bromostyrene, vinyl toluene, and the like. Alkenylaromatic polymers also include homopolymers of styrene (commonlyreferred to as “polystyrene” or “polystyrenic resin”) and alsocopolymers of styrene and butadiene (commonly referred to as “impactpolystyrene”).

[0022] The terms “polystyrenic resin” or “polystyrene,” as used herein,include homopolymers of styrene and styrene copolymers comprised of atleast 50 mole percent of a styrene unit (preferably at least about 70mole percent) and a minor (i.e., less than 50%) proportion of a monomercopolymerizable with styrene. The terms “polystyrenic resin” or“polystyrene,” as used herein, also include blends of at least 50 wt. %of the styrene homopolymer (preferably at least about 60 wt. %) withanother predominately styrenic copolymer. The physical blends arecombined in a dry form after the blends have previously beenpolymerized.

[0023] The polystyrenic resin used in the present invention may be anyof those homopolymers obtained by polymerizing styrene to a weightaverage molecular weight (M_(w)) of from about 100,000-450,000 (commonlyreferred to as “crystal polystyrene”), or any of those graft copolymersobtained by polymerizing a blend of polymerized styrene upon a nucleusof styrene butadiene rubber (SBR) to a weight average molecular weightof from about 100,000-350,000 (commonly referred to as “impactpolystyrene”).

[0024] Impact polystyrenes are generally classified as medium impactpolystyrene (MIPS), high impact polystyrene (HIPS), or super high impactpolystyrene (S-HIPS). The butadiene level of the impact polystyrene ispreferably in the range from about 3-10 wt. % of the copolymer(butadiene and polystyrene). The impact polystyrene generally has a meltflow index of less than about 5 g/10 min., and preferably less thanabout 3 g/10 min.

[0025] The alkenyl aromatic polymer used in the present invention may beobtained by blending two or more alkenyl aromatic polymers. For example,blends of crystal polystyrene and impact polystyrenes, such as crystalpolystyrene and HIPS, may be blended to comprise the alkenyl aromaticpolymer.

[0026] The term “polyolefin,” as used herein, includes polypropylenes,polyethylenes, and polybutenes. The term “polypropylene,” as usedherein, includes polymers of propylene or polymerizing propylene withother aliphatic polyolefins, such as ethylene, 1-butene, 1-pentene,3-methyl-1-butene, 4-methyl-1-pentene, 4-methyl-1-hexene,5-methyl-1-hexene, and mixtures thereof. Polypropylene not only includeshomopolymers of propylene, but also propylene copolymers comprised of atleast 50 mole percent (preferably at least 70 mole percent) of apropylene unit and a minor proportion of a monomer copolymerizable withpropylene and blends of at least 50 wt. % of the propylene homopolymerwith another polymer.

[0027] The term “polyethylene,” as used herein, includes polymers ofethylene, such as low density polyethylene (LDPE), medium densitypolyethylene (MDPE), high density polyethylene (HDPE), very low densitypolyethylene (VLDPE), linear low density polyethylene (LLDPE),metallocene-catalyzed linear low density polyethylene (mLLDPE), andcombinations thereof.

[0028] LDPE is generally defined as an ethylenic polymer having aspecific gravity of from about 910-925 kg/m³. MDPE is generally definedas an ethylenic polymer having a specific gravity between the LDPEs andthe HDPEs (i.e., from about 925-940 kg/m³). The term polyethylene, asused herein, includes homopolymers of ethylene and copolymers comprisedof at least 50 mole percent of an ethylene unit (preferably at least 70mole percent) and a minor (i.e., less than 50%) proportion of a monomercopolymerizable with the ethylene unit. The term LDPE, as used herein,also includes physical blends of two or more different homopolymers thatare classified as LDPEs. Similarly, the term MDPE and HDPE may alsoinclude blends of two or more different homopolymers classified as MDPEsand HDPEs, respectively.

[0029] HDPE used in the present invention generally has a specificgravity of from about 940-970 kg/m³. The M_(z) is generally greater thanabout 1,000,000 and may be greater than about 1,200,000. The z-averagemolecular weight (M_(z)) is characterized by a concentration ofextremely high molecular weight polymer chains (i.e., those near anupper end of the molecular weight distribution). The HDPE generally hasa polydispersity index, D=M_(w),/M_(n), in the range of from about12-20.

[0030] VLDPE used in the present invention generally has a density fromabout 880-912 kg/m³, more commonly from about 890-910 kg/m³, and a meltindex of from about 0.5-5 g/10 min., preferably from about 1-3 g/10 min.

[0031] LLDPE used in the present invention generally has from about 1-20wt. %, and preferably from about 1-10 wt. %, of higher alpha olefinmonomer copolymerized therein. In addition, the alpha olefin monomeremployed in the ethylenic copolymer may be selected from the groupconsisting of 1-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 1-hexene,4-methyl-1-pentene, 3-methyl-1-hexene, 1-octene, and 1-decene. The LLDPEresins that may be used in the present invention have densities fromabout 890-940 kg/m³, more commonly from about 900-930 kg/m³, and meltindices (I₂) of from about 1-10 g/10 min. as determined by ASTM D1238.

[0032] The mLLDPE is a polymer having a low polydispersity. The lowpolydispersity polymer may be prepared from a partially crystallinepolyethylene resin that is a polymer prepared with ethylene and at leastone alpha olefin monomer (e.g., a copolymer or terpolymer). The alphaolefin monomer generally has from about 3-12 carbon atoms, preferablyfrom about 4-10 carbon atoms, and more preferably from about 6-8 carbonatoms. The alpha olefin comonomer content is generally below about 30wt. %, preferably below about 20 wt. %, and more preferably from about1-15 wt. %. Exemplary comonomers include propylene, 1-butene, 1-pentene,1-hexene, 3-methyl-1pentene, 4-methyl-1-pentene, 1-octene, 1-decene, and1-dodecene.

[0033] The low polydispersity polymer has a density of from about880-940 kg/m³. The polydispersity polymer should have a molecular weightdistribution, or polydispersity, (M_(w)/M_(n), “MWD”) within the rangeof from about 1-4, preferably from about 1.5-4, more preferably fromabout 2-4, and even more preferably from about 2-3. The melt flow ratio(MFR) of these polymers, defined as I₂₀/I₂ and as determined inaccordance with ASTM D1238, is generally from about 12-22, withpreferably lower and higher limits of about 14-20, respectively. Themelt index (MI), defined as the I₂ value, should be in the range of fromabout 0.5-10 g/10 min., and preferably with lower and upper limits ofabout 1-5 g/10 min., respectively, as determined by ASTM D1238.

[0034] An example of a “polybutene” includes a polymer of isobutene. Anexample of a “polyethylene terephthalate” includes a polyester resinmade from ethylene glycol and terephthalic acid. An example of a“polyester” includes a polyester resin which is a polycondensationproduct of a dicarboxylic acid with a dihydroxy alcohol.

[0035] According to a preferred embodiment, first layer 12 of supportbacker board system 10 is formed by extruding an alkenyl aromaticpolymer, such as a polystyrenic resin. Polystyrenic resins are generallypreferred because they provide more stiffness to support backer boardsystem 10 than other materials, such as polyethylene as measured by ASTMD1037-87 and ASTM D1621-73. Also, at the present time, polystyrenicresins are more economical to use than other contemplated resins forforming first layer 12. A preferred polystyrenic resin for use in firstlayer 12 is a blend of impact polystyrene and crystal polystyrene. Theblend of impact polystyrene and crystal polystyrene may include virginand reprocessed or reclaimed material.

Second And Fourth Layers

[0036] Optional second layers 14 and 18 of support backer board system10 may be independently formed from any of the following resins: alkenylaromatic polymers, polyolefins, polyethylene terephthalate (PET),polyesters, and combinations thereof. Second layer 14 and fourth layer18 are generally each from about 0.5-3.0 mils in thickness, and morespecifically from about 0.8-2.0 mils.

[0037] According to one embodiment, at least one of second layer 14 andfourth layer 18 of support backer board system 10 are formed fromalkenyl aromatic polymers. At the present time, polystyrenic resins aremore economical to use than other contemplated resins for forming secondand fourth layers 12, 16. The preferred polystyrenic resin is impactpolystyrene and, more specifically, high impact polystyrene.

[0038] According to another embodiment, at least one of second layer 14and fourth layer 18 are film layers. Second layer 14 and fourth layer 18may be metallized or foil. Second layer 14 and fourth layer 18 may besingle or biaxially orientated. A polystyrene-based film that may beused is DOW TRYCITE®. The preferred film layer is formed from apolyolefin. A preferred polyolefin for use in forming second layer 14and fourth layer 18 is polypropylene. The polyolefin film used informing second layer 14 and fourth layer 18 generally has an ultimatetensile as measured by ASTM D882 of greater than about 3700 psi, and apercent elongation as measured by ASTM D882 of greater than about 450%.

Third Layer

[0039] Third layer 16 of support backer board system 10 may be formedfrom any of the following resins: alkenyl aromatic polymers,polyolefins, polyethylene terephthalate, polyesters, adhesives, andcombinations thereof.

[0040] The term “adhesive,” as used herein, includes any material whichis capable of chemically bonding one layer of support backer boardsystem 10 to another layer. Examples of suitable adhesives includeethylene vinyl acetate (EVA), a mixture of EVA in polyethylene, blockcopolymers comprising polymeric regions of styrene-rubber-styrene, suchas KRATON® made by SHELL® Chemical Company, and a modified EVA, such asBYNEL® made by DuPONT®. Modified EVAs generally have melt indices fromabout 6.4-25 g/10 min. as measured by ASTM D1238, and densities fromabout 923-947 kg/m³ as measured by ASTM D1505. The adhesive may be amixture of EVA in polyethylene, with the preferred amount being at least15% EVA in polyethylene. Preferred adhesives for third layer 16 areKRATON® and BYNEL®, as described above.

[0041] If third layer 16 is not an adhesive, it is generally from about0.8-3.0 mils in thickness, with the preferred thickness being from about0.8-2.0 mils. If third layer 16 is an adhesive, the thickness of thirdlayer 16 is generally from about 0.15-0.5 mils in thickness.

Additional Layers

[0042] It is contemplated that additional layers may be used in supportbacker board system 10. For example, support backer board system 10 ofFIGS. 1-3 may contain optional laminated surface coatings or “facers.”The optional facers provide additional durability and bendability tosupport backer board system 10. The optional facers may be a metallizedfilm or foil. The optional facers may be added to an existing outerlayer(s), such as to the outer surfaces of second layers 14 of FIG. 2.To enhance the R-value, a reflective facer may be used if there existsan air space between the layers. The facers will generally have areflectivity greater than 90%. Support backer board system 10 may alsoinclude additional layers, as described above, with respect to firstlayer 12, second layer 14, third layer 16, and fourth layer 18.

Support Backer Board System

[0043] The individual layers of support backer board system 10 may bebonded by attaching, adhering, fusing, or the like. For example, thelayers may be thermally or chemically bonded to one another. Whether alayer is thermally or chemically bonded depends upon the selectedresin(s) of one layer and that of the adjacent layer. Thermal bondingmay be accomplished by any conventional manner to fuse the polymericsurfaces, including use of a flameless air torch, heated rolls, andinfrared heating.

[0044] Chemical bonding may be accomplished by using a chemicalattaching means, such as an adhesive. Optionally, an additional layer orlayers may be added to support backer board system 10 between any of theadjacent layers to chemically bond the adjacent layers. For example, anadhesive may be used between first layer 12 and second layer 14.Likewise, a second adhesive may be used between any of the remaininglayers to bond the layers to one another. It is also contemplated thatone or more adhesives may be preattached to a layer, coextruded onto alayer, or applied via conventional adhesive bonding methods.

[0045] Referring to FIG. 4a, siding system 20 includes support backerboard system 10, siding 22, and plywood 24. It is contemplated thatplywood 24 may be replaced by another material, such as orientatedstrand board (OSB), other foamed sheathings (such as extrudedpolystyrene, polyisocyanurate (also referred to as “isoboard”)),beadboard, hardboard, blackboard, fiberboard, or existing siding. Sidingsystem 20 is typically attached to an installation board, such as a 2×4ft. board (not shown). As shown in siding system 20 of FIGS. 4a and 4 b,support backer board system 10 is located on an interior surface ofsiding 22 and an outer surface of plywood 24. Support backer boardsystem 10 may be attached to siding 22 by a variety of methods, such asbeing attached mechanically by fasteners, such as nails, screws,staples, and the like. Support backer board 10 may also be adheredchemically by adhesives and the like to siding 22. In one type of siding22 shown in FIG. 5, a plurality of holes 25 are formed therein to assistin attaching siding 22 and support backer board system 10. Typically,the attachment of siding 22 and support backer board system 10 occurs atessentially the same time as the attachment of support backer boardsystem 10 and plywood 24. Of course, support backer board system 10 maybe separately attached to siding 22 and plywood 24.

[0046] The support backer board system may be used with siding in bothcommercial and residential structures. Additionally, the support backerboard system may be used in new construction and in remodeling orretrofitting of existing construction.

[0047] It is contemplated that the support backer board system may beused on siding systems other than shown in FIGS. 4a and 4 b.

Properties Of The Support Backer Board System

[0048] Support backer board system 10 used in the present inventioncomprises at least first layer 12. It is preferable that at least onelayer of support backer board system 10 be an alkenyl aromatic polymer(e.g., a polystyrene), due to economical considerations.

[0049] Support backer board system 10 having a first layer made of afoamed material generally has a density as measured by ASTM D1622-88from about 1.0-6.0 lbs/ft³, with preferred lower and upper limits ofabout 2.0-5.0 lbs/ft³, respectively. The optional second and fourthlayers, if a solid layer (i.e., a non-foamed layer), generally have adensity of from about 54.0-69.0 lbs/ft³. The optional third layer, if asolid layer, generally has a density of from about 54.0-69.0 lbs/ft³.

[0050] Support backer board system 10 used in the present inventionprovides support to the siding, and exhibits good stiffness and strengthin the machine direction as measured by ASTM D1037-87. Support backerboard system 10 generally has a machine direction (MD) average flexuralstrength stress at yield of greater than about 200 psi as determined byASTM D1037-87. The MD average flexural strength stress at yield ispreferably greater than about 225 psi, most preferably is greater thanabout 250 psi, and even more preferably is greater than 275 psi. Supportbacker board system 10 generally has a transverse direction (TD) averageflexural strength stress at yield of greater than about 130 psi asdetermined by ASTM D1037-87. The TD average flexural strength stress atyield is preferably greater than about 150 psi, most preferably isgreater than about 170 psi, and even more preferably is greater than 190psi.

[0051] Support backer board system 10 generally has an MD average loadat yield greater than about 2.5 lbs as determined by ASTM D1037-87. TheMD average load at yield is preferably greater than about 2.75 lbs, morepreferably is greater than about 3.0 lbs, and most preferably is greaterthan about 3.25 lbs. Support backer board system 10 generally has a TDaverage load at yield greater than about 1.5 lbs as determined by ASTMD1037-87. The TD average load at yield is preferably greater than about1.75 lbs, more preferably is greater than about 2.0 lbs, and mostpreferably is greater than about 2.25 lbs.

[0052] Support backer board system 10 generally has an MD averagecompressive strength at 10% deflection of greater than about 10 psi asdetermined by ASTM D1621-73. The MD average compressive strength at 10%deflection is preferably greater than about 12 psi, and most preferablyis greater than about 18 psi.

[0053] Support backer board system 10 that is perforated generally has awater vapor transmission rate (WVTR) of greater than 1.0, and preferablygreater than 1.8 as determined by ASTM E96 (Procedure A). A perforatedboard is typically used in remodeling where a warm side vapor barrier isnot present. For a support backer board system in new construction(without perforations), the WVTR is less than 1.0, and preferably lessthan about 0.8 as determined by ASTM E96 (Procedure A).

[0054] Support backer board system 10 used in the present invention maybe formed into a number of shapes. For example, support backer boardsystem 10 may be a board sheet or a folded or hinged board (commonlyreferred to as “fanfold board”). The fanfold board is designed to unfoldat its hinges and includes a number of individuals panels. A preferredshape is a fanfold board because it reduces labor costs by havingadditional coverage per unit. This saves time in transporting thematerials to the site and during installation. Additionally, fanfoldedboards also reduce the possibility of spaces forming during theinstallation of adjacent support backer board systems as compared toboard sheets since fanfolded boards typically cover a large surface areaof the siding.

[0055] Support backer board system 10 used in the present invention maybe manufactured in a variety of sizes. Popular sizes used in newconstruction or remodeling siding applications include 2′×8′ (2 feet×8feet), 4′×8′, and 4′×9′ board sheets. Popular fanfold sizes include4′×24′ and 4′×50′, which include a number of individual panels for easyinstallation and labor savings.

[0056] Support backer board system 10 may also vary in thicknessdepending on the selected materials. If a foamed alkenyl aromaticpolymer is used, the thickness of support backer board system 10 isgenerally from about 125500 mils as measured by ASTM D1622-88. Thepreferred thickness of support backer board system 10 is from about250-375 mils. If a solid polyolefin or a solid alkenyl is used, thethickness of support backer board system 10 is generally from about20-80 mils.

[0057] The layers of support backer board system 10 generally vary intheir respective weight percent relative to each other. Support backerboard system 10 generally comprises from about 50-100 wt. % of firstlayer 12. The remainder of support backer board system 10 (0-50 wt. %)comprises second layer 14, third layer 16, fourth layer 18, and anyadditional layers. Preferably, support backer board system 10 comprisesfrom about 60-85 wt. % of first layer 12, and most preferably from about65-75 wt. % of first layer 12. In general, first layer 12 is preferablyincreased on a percentage basis when the thickness of support backerboard system 10 is increased because of economic considerations.

Methods For Forming A Support Backer Board System

[0058] A process that may be used in forming a support backer boardsystem is described below. The process includes extruding at least afirst layer and thermoforming the support backer board system into adesired shape in which the desired shape is generally contour to theselected siding.

[0059] According to one process, pellets of a polymeric resin(s), suchas alkenyl aromatic polymers, polyolefins, polyethylene terephthalate(PET), polyesters, and combinations thereof in their solid form, areloaded into an extrusion hopper. The pellets of the polymeric resin(s)are to be used in forming at least the first layer of the support backerboard system.

[0060] A nucleating agent (also referred to as “cell size controlagent”) or combination of such nucleating agents may be employed in theprocess for advantages, such as their capability for regulating cellformation and morphology. The amount of nucleating agent to be addeddepends on the desired cell size, the selected blowing agent, and thedensity of the polymeric composition. Known nucleating agents, such astalc, mixtures of sodium bicarbonate and citric acid, and the like, maybe employed in this process.

[0061] It is contemplated that stability control agent(s) may also beadded to the polymeric resin(s), including conventional stabilitycontrol agents. Some examples of stability control agents that may beused include, but are not limited to, glycerol monostearate, saturatedhigher fatty acid amides, and glycerol monoester of a C₂₀-C₂₄ fattyacid.

[0062] If desired, fillers, colorants, light and heat stabilizers,plasticizers, chemical blowing agents, flame retardants, foamingadditives, and plastic compounding agents can be added to the polymericcomposition. The polymeric composition comprises the polymeric resinand, if added, the nucleating agent, the stability control agent, andadditives. The polymeric composition is conveyed through a feed zone ofthe extruder and heated at a temperature sufficient to form a polymericmelt.

[0063] A physical blowing agent is added at an injection port area ofthe extruder in an appropriate ratio to the target density. The selectedblowing agent may be any type that is capable of producing foam with theselected resin. Some examples of blowing agents include physical blowingagents, such as halocarbons, hydrocarbons, or combinations thereof.Examples of these include commercially available hydrofluorocarbons(such as HFC-152a and HFC-134a), hydrochlorofluorocarbons (such asHCFC-22, HCFC-141b, and HCFC 142b) and the C₃-C₆ hydrocarbons. Othertypes of blowing agents include carbon dioxide. The polymericcomposition and selected blowing agent are thoroughly mixed within theextruder in a mixing zone, and subsequently cooled in a cooling zone.The cooled polymeric blowing agent melt is extruded through a die.

[0064] As shown in one process (see FIG. 6), the polymeric foam to beeventually used in forming first layer 12 is extruded from an extruder30 through round die 32. After exiting round die 32, the extrudateexpands when entering a lower pressure region (e.g., the atmosphere) andforms a polymeric web of foam. The polymeric web of foam is stretchedover a sizing drum or mandrel 34 to size the web of foam.

[0065] The outer surfaces of polymeric web 36 are typically cooled so asto form a “skin.” The skin is typically about a few thousand (or a fewmils) thick, but may vary depending on the cooling employed. The skinprovides additional strength and also a smoother surface, which is moreaesthetically pleasing to a consumer. It is contemplated that themethods for cooling can include water and air. The skinning may beperformed, for example, by stretching polymeric web 36 over sizing drum34 with optional cooling, wherein an inner surface of polymeric web 36is cooled.

[0066] A polymeric web 36 proceeds to travel around an S-wrap of rollers38 a-c in which roller 38 a is an idler roller and rollers 38 b and 38 care driven or pull rollers. Polymeric web 36 will form first layer 12 ofsupport backer board system 10. Driven rollers 38 b, 38 c assist inmoving polymeric web 36 through this process. Polymeric web 36 proceedsthrough two idler rollers 40 a,b before proceeding between two drivenrollers 42 a,b. Driven rollers 42 a,b assist in maintaining a consistentsurface for which to add an optional second layer 14 via a coating orlaminating machine 44. Coating machine 44 may be any conventionalmachine that is capable of applying an optional laminated surfacecoating to polymeric web 36. The laminated surface coating willeventually form second layer 14 of support backer board system 10.Coating machine 44 is also optional to this process. Polymeric web 36,including the optional laminated surface coating, continues proceedingthrough a plurality of idler rollers 46. It is contemplated thatpolymeric web 36 may be processed to include printing on a surface(s) orother treatments.

[0067] Polymeric web 36 proceeds through the opening between two drivennip or polish rollers 48 a,b. At this opening, a second optionallaminated surface coating is added to polymeric web 36 and the firstoptional laminated surface coating via a coating or laminating machine50. Coating machine 50 may be any conventional machine that is capableof applying a second optional laminated surface coating. The secondoptional laminated surface coating will eventually form an outer layer,such as second layer 14 (see FIG. 2). At this point, the optionallaminated surface coating(s) and polymeric web 36 form a support backerboard system.

[0068] The support backer board system proceeds to driven roller 52 andaround a plurality of idler rollers 54. In an alternative embodiment,roller 52 is an idler roller that, along with the plurality of idlerrollers 54, may be located generally parallel to roller 48 b such thatthe laminated surface coating(s) and polymeric web 36 proceed in agenerally horizontal direction after exiting between rollers 48 a,b.

[0069] The support backer board system proceeds towards an optionalperforating creasing machine 62. The optional perforating creasingmachine 62 may include any conventional equipment that is capable offolding the support backer board system into a fanfold board system. Ofcourse, if a sheet board system is desired, the creasing equipmentshould not be included in the process. A perforating machine, however,may be used to produce a sheet board system. The optional perforatingcreasing machine may be located after thermoformer 64.

[0070] As shown in FIG. 6, the support backer board system proceedstowards thermoformer 64. The support backer board system is formed intoa desired shape in thermoformer 64. The desired shape is generallycontour to the selected siding. One example of thermoforming includesforming or shaping a polymeric web or sheet by heating the web near itssoftening point, fitting it along the contours of a mold with pressuresupplied by vacuum or other force, and removing it from the mold aftercooling below its softening point. The thermoforming may be performed asan “in-line” process or an “off-line” process. An “in-line”thermoforming process, as used herein, is defined as a continuousprocess with the extrudate steps as shown in, for example, FIG. 6. Thein-line thermoforming process may not need a heating oven or tunnelsince the extrudate may already be at an appropriate temperature to bethermoformed. An “off-line” thermoforming process, as used herein, isdefined as a non-continuous process with the extrudate steps, as shownin FIG. 7a and 7 b described below.

[0071] Referring to FIG. 6, according to one embodiment, thermoformer 64includes a heated tunnel where the support backer board system isheated. The temperature of a heating tunnel will vary depending on thepolymeric material. Generally, the heating tunnel will operate at atemperature from about 350-500° F. The heated support backer boardsystem then continues into the mold and is formed or contoured thereinto its desired shape by pressure from a vacuum. The molds used inthermoformer 64 may vary in size and shape. These different sizes andshapes generally correspond to the design of the siding. An “in-line”process may be run at a speed of about 140 ft/min., and generally runsat a speed of about 120 ft/min. The speed will vary on factors such aschain cycle time and the amount of mold closed time for cooling.

[0072] The support backer board system is then cut to a desireddimension by shearing equipment 66. Shearing equipment 66 may be anyequipment capable of cutting the support backer board system intodesired dimensions. It is also contemplated that other finishingoperations may occur, such as packaging, folding and/or trimming.

[0073] It is contemplated that the perforation of the support backerboard system may occur after thermoformer 64. The trimming and creasingof the support backer board system may occur in the mold.

[0074] Referring to the “off-line” process of FIGS. 7a and 7 b, theprocess includes additional steps which were not included in the processof FIG. 6. Referring to FIG. 7a, the process includes a roller or winder56 which rolls the support backer board system. Referring to FIGS. 7aand 7 b, rolled support backer board system 58 proceeds to an unwinder60. Unwinder 60 unwinds rolled support backer board system 58. As shownin FIG. 7b, the unwound support backer board proceeds to optionalperforating creasing machine 62, thermoformer 64, and shearing equipment66. An “off-line” process may be run at a speed of about 140 ft/min.,and generally runs at a speed of about 120 ft/min. An “off-line” processmay operate at speeds lower than an “in-line” process depending onwhether additional time is necessary for the support backer board systemto reach an appropriate temperature.

Methods For Using Support Backer Board Systems

[0075] The support backer board systems are used with siding. Siding, asused herein, is defined as protective facing or cladding on a surface.In addition to protection, such as repelling water, siding has anaesthetic value. Siding is typically adapted to cover walls or othersurfaces of a structure in both residential and commercial settings. Thesiding is typically vinyl, but may also include polymer-like materialsand the like. It is contemplated that siding may be made of othermaterials in which additional support to the siding is desired. Commoncommercial types of siding include 4″, 4.5″, and 5″ Doubles, and 4″,4.5″, and 5″ Double Dutch.

[0076] While the present invention has been described with reference toone or more particular embodiments, those skilled in the art willrecognize that many changes may be made thereto without departing fromthe spirit and scope used in the present invention. Each of theseembodiments and obvious variations thereof is contemplated as fallingwithin the spirit and scope of the claimed invention, which is set forthin the following claims.

What is claimed is:
 1. A method for using a support backer board systemand siding, said support backer board system comprising at least a firstlayer, the method comprising the steps of: providing siding; extruding afirst layer, said first layer being made from a material selected fromthe group consisting of alkenyl aromatic polymers, polyolefins,polyethylene terephthalate, polyesters, and combinations thereof;thermoforming said board system into a desired shape, said desired shapebeing generally contour to said selected siding; and attaching saidsiding to said board system so as to provide support thereto.
 2. Themethod of claim 1 , wherein said siding is made from vinyl orpolymer-like materials.
 3. The method of claim 1 , wherein said boardsystem is fanfolded.
 4. The method of claim 1 , wherein said boardsystem is a sheet.
 5. The method of claim 1 , wherein said thermoformingstep is performed as an in-line process.
 6. The method of claim 1 ,wherein said thermoforming step comprises placing the extrudated boardsystem in a mold and forming the board system into a desired shape underpressure.
 7. The method of claim 1 , wherein said thermoforming step isperformed as an off-line process.
 8. The method of claim 7 , whereinsaid thermoforming step comprises heating the extrudated board system,placing the heated extrudated board system in a mold, and forming theboard system into a desired shape under pressure.
 9. The method of claim1 , wherein the first layer is an alkenyl aromatic polymer.
 10. Themethod of claim 9 , wherein the alkenyl aromatic polymer is polystyrene.11. The method of claim 1 , wherein said board system further comprisesa second layer, said second layer being made from a material selectedfrom the group consisting of alkenyl aromatic polymers, polyolefins,polyethylene terephthalate, polyesters, and combinations thereof. 12.The method of claim 11 , wherein said board system further comprises athird layer, said third layer being made from a material selected fromthe group consisting of alkenyl aromatic polymers, polyolefins,polyethylene terephthalate, polyesters, adhesives, and combinationsthereof.
 13. The method of claim 1 , wherein said board system comprisesa first layer, a second layer, a third layer, and a fourth layer, saidfirst layer being comprised of a polystyrene, said second layer beingcomprised of a polystyrene or a polyolefin, said third layer beingcomprised of an adhesive, and said fourth layer being comprised of apolystyrene or a polyolefin.
 14. The method of claim 1 , wherein thestep of attaching includes using nails, screws, staples, or acombination thereof.
 15. The method of claim 1 , wherein said boardsystem has a thickness from about 125-500 mils.
 16. The method of claim1 , further comprising the steps of providing a material selected fromplywood, orientated strand board, foamed sheathings, beadboard,hardboard, blackboard, fiberboard, and existing siding, and attachingsaid board system and said material.
 17. A method for using a supportbacker board system and siding, said support backer board systemcomprising at least a first layer, the method comprising the steps of:providing siding; extruding a first layer, said first layer being madefrom at least one alkenyl aromatic polymer; thermoforming said boardsystem into a desired shape, said desired shape being generally contourto said selected siding; and attaching said siding to said board systemso as to provide support thereto.
 18. The method of claim 17 , whereinsaid alkenyl aromatic polymer is polystyrene.
 19. The method of claim 17, wherein said siding is made from vinyl or polymer-like materials. 20.The method of claim 17 , wherein said thermoforming step comprisesplacing the extrudated board system in a mold and forming the boardsystem into a desired shape under pressure.